CO2 injection point

tennis4you

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Does it matter where you inject the CO2 into the tank?

For example. I have a 125 gallon tank, 6' long. Does it matter if the CO2 is injected into the tank at the top or the bottom? I have a DIY reactor, so I am sure it is not as efficient as the real deal.

Right now I am injecting the CO2 near the top on one side. Just wondering what is the most efficient.
 

ceg4048

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Yes, it can definitely matter in a big tank. Even in not so big tanks it matters if circulation and flow are marginal. The CO2 concentration has to travel from the injection point to the furthest reaches of the tank and that's why I like the external solution. This means the water entering the tank is already saturated. For an in-tank diffuser I like to place the diffuser beneath the filter outflow or powerhead pointing downwards so that the CO2 is carried into the tank. If your diffuser is far away from the source of flow it takes much longer to saturate the water. In a large tank multiple diffusers work much better than a single diffuser. This adds complication but in this case it definitely adds value.

Cheers,
 

tennis4you

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So the "external solution" is the reactor? I have the DIY (Came with the CO2 tank and equipment I bought used) reactor and it is hooked to the outflow tube of the canister filter. Mixes before it shoots into the tank. I assume that is what is best?
 

ceg4048

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Well it's what I found works best for my configuration. If you have both types then try either for a few weeks and see what difference it makes. If possible, try using both simultaneously. You know I'm never sure what the marketing terms are, whether that is "reactor" or "diffuser" but I always know the difference between external and internal. Those distinctions are unambiguous. :D

Cheers,
 

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